Throttle control for compound carburetors



Aug. 16, 1955 H. A, CARLSON ET AL 2,715,522

THROTTLE CONTROL FOR COMPOUND CARBURETORS Filed Dec. 26, 1951 4 Sheets-Sheet l INVENTORS. HAROLD A. CARLSON Y JAMES T.W. MOSELEY g- 16, 1955 H. A. CARLSON ET AL 2,715,522

THROTTLE CONTROL FOR COMPOUND CAPJBURETORS Filed Dec. 26, 1951 4 Sheets-Sheet 2 INVENTORS. HAROLD A. CARLSON Y JAMES T. W. MOSELEY ATTORNEY Aug. 16, 1955 H. A. CARLSON ET AL 2,715,522

THROTTLE CONTROL FOR COMPOUND CARBURETORS Filed Dec. 26, 1951 4 Sheets-Sheet 3 FIG.IO.

INVENTORS'. HAROLD A. CARLSON BY JAMES T.W. MOSELEY ORNEY 16, 1955 H. A. CARLSON ETAL 2,715,522

THROTTLE CONTROL FOR COMPOUND CARBURETORS Filed Dec. 26, 1951 4 Sheets-Sheet 4 INVENTORS. HAROLD A.CARLSON JAMES T.W. MOSELEY ATTORNEY United States Patent Ofilice 2,715,522 Patented Aug. 16, 1955 THROTTLE CONTRQL FOR COISHOUND CARBIIRETGRS Harold A. Carlson, Erentwood, and James T. W. Moseley,

Richmond Heights, Ma, assignors to Carter Carburetor Corporation, St. Louis, Mo., a corporation of Delaware Application December 26, 1951, Serial No. 263,291

9 Claims. (Cl. 261-39) This invention relates to carburetion systems, particularly of the muti-stage type, for internal combustion engines.

There has been a recent trend toward providing larger automobile engines with carburetion systems which au tomatically reduce the quantity of carbureted mixture under low speed, high load conditions by cutting off one or more mixture supply conduits. In some cases, the auxiliary or secondary induction conduit or conduits are cut off by a separate valve which is actuated by the direct pressure of gases thereon. However, we prefer to operate the throttle valves serially by means of a linkage connection between the main, manually operated throttle valve or valves and the auxiliary valve or valves. With the latter arrangement, we have found that it is desirable to prevent opening of the auxiliary mixture conduit or conduits at low temperatures, as during starting and warm-up, irrespective of the main throttle position, since the bringing in of the auxiliary mixture supply at such times has an adverse efiect upon engine operation.

Accordingly, this invention consists in novel means for preventing opening of the auxiliary mixture conduit or conduits and, more particularly, the throttle valve or valves therein, in accordance with the temperature. Since the carburetor is provided with a thermostatic choke valve, we utilize the choke valve control as a part of the look-out mechanism for the auxiliary throttle Valve or valves. Where such lock is provided, it is necessary to provide control linkage between the main and auxiliary throttle valves which permits partial opening of the main throttles before the auxiliary throttle valves start to open under normal operating conditions and is capable of yielding, in case the auxiliary throttle valve or valves are locked, to permit continued opening of the main throttle valve.

The invention is illustrated in the accompanying drawings in which:

Fig. 1 is a side view of a four-barrel, two-stage carburetor embodying the invention, parts being broken away and sectioned to show the underlying structure.

Fig. 2. is a side View of the auxiliary throttle lock-out mechanism in unlocked position.

Fig. 3 shows parts of the structure in Fig. 2, but with the fast idle cam removed.

Fig. 4 is an elevation of the carburetor taken from the opposite side from Fig. 1, a part being broken away and sectioned.

Fig. 5 shows the throttle interconnection linkage with the main, manual throttle valves partially opened to the extent of the lost motion provided between the main and auxiliary valves.

Fig. 6 is a view of the parts in Fig. 5, but showing the auxiliary throttle valves locked closed and the main throttles substantially fully opened.

Fig. 7 is a view of the parts in Figs. 5 and 6 and showing all throttle valves substantially fully opened.

Figs. 8 and 9 are views of two of the levers utilized in the throttle interconnection mechanism.

Fig. 10 is a top view of the carburetor, portions being broken away and sectioned.

Fig. 11 is a vertical, transverse section through the carburetor taken on line 11-11 of Fig. 10.

Fig. 12 is a partial, vertical, transverse section taken on line 12-12 of Fig. 10.

The carburetor, as best shown in Fig. 10, has four barrels or mixture conduits, including two forward main conduits 15 and 16 and two rear, auxiliary conduits 17 and 18 all arranged compactly side by side in a single, integrally formed carburetor. At the top of the carburetor is a generally rectangular air inlet portion 19 having a transverse partition 20. A transverse shaft 21 journalled in the air horn mounts an unbalanced choke valve 22 which controls the entrance of air to the forward,

main mixture conduits 15 and 16. As shown in Figs. 1 and 11, butterfly throttle valves 23 and 24 are mounted, respectively, in the lower discharge portion of the main and auxiliary mixture conduits upon transverse journalled shafts 25 and 26. Consequently, each pair of throttle valves 25 and 26 moves as a unit.

Rigid with main throttle shaft 25 at one end (Fig. 1) is a double arm crank 27, apertured as at 28, for attachment by means of the usual linkage (not shown) to the accelerator pedal. Another lever 29, also rigid with main throttle shaft 25, carries an idle speed adjusting screw 30. A small, disk-like member 32 is rigidly secured to the corresponding end of the other throttle shaft 26 and has a small radial lug 33.

Pivotally mounted on a stub shaft 35 between and slightly above the members just described are fast idle cam elements 36 and 37 which are resiliently secured together by means of a torsion spring 38 so that a lug 39 on part 37 bears against part 36 within recess 40 thereof. Also loosely pivoted on stub shaft 35 is an eccentrically Weighted stop device 41, best shown in Fig. 3, having a finger 42 which, in the position to which this part is normally biased by its own weight, lies, at its extremity, in the path of lug 33 on disk member 32 rigid with auxiliary throttle shaft 26 so as to prevent opening of the auxiliary throttle valve. As shown. in Fig. 1, the extremities of finger 42 and lug 33 lie substantially on .a radius extending from the center of stub shaft 35 to provide a stable stop device which cannot be forced out of the way merely by the application of force thereto through locking lug 33.

Fast idle cam part 37 is connected by a link 44 to an arm 45 rigid with choke shaft 21 so that, when the choke valve is closed, outer portion 36 of the fast idle cam device is presented to be engaged by idle adjusting screw 39 to limit closing movement of main throttle valves 23 to the fast idle position, as is Well known. When the choke valve is opened, part 36 of the fast idle cam no longer interferes with the closing of the main throttle valves to their normal idle positions. Main throttle control lever 27, previously mentioned, has an arm 46 which, when the main throttle valves are substantially fully opened, engages a finger 47 on fast idle cam part 36 so as to slightly rotate the cam clockwise and, thereby, partially open the choke valve for unloading any excess fuel which may be in the manifold. Since opening movement of the choke valve under normal influence of its thermostatic control, mounted in housing 50, shifts the fast idle cam parts clockwise, lug 48 will be brought against eccentric weighted lever 41, as shown in Figs. 2 and 3, as the engine approaches its normal running temperature to free the auxiliary throttle valves.

Figs. 49 show the opposite side of the carburetor, including the parts forming a resilient, lost motion connection between the main and auxiliary throttle valves. Loosely pivoted about this end of main throttle shaft 25 are a pair of levers and 56, best shown in Figs. 8 and 9.

' fuel mixture 'to 'the engine.

closing movements of'the main throttle valves finger 62 auxiliary throttle valves.

in their closing movement, reach the partial opening 7 closed.

J A small, disk-like arm 57, rigid with shaft 25, has an angular finger 58 resiliently connected by means of a coiled tension spring 59 to the extremity of a projection 60 on lever, 55. This spring normally maintains an outwardly turned finger 61 on lever 55 in contact with a radial finger 62 on tight arm 57, as shown in Figs. 4, and 7. Lever alsohas an inwardly turned peripheral finger. 63 which lies in the same vertical plane as a portion 64 of lever 56. Inner, loose lever 56 also has a 111g 65 on its outer face to be engaged by an elbow 66 on lever 55 (Fig. 4) to positively urge lever 56 in the clockwise direction. 7

Lever 56 is connected at its extremity, by a link 69, to a crank 70 rigid with the corresponding extremity of auxiliary throttle valve shaft 26. 7 A tension spring 71, stressed'between the upper extremity of crank 70 and an 'apertured lug 72 .on the carburetor body normally urges the auxiliary throttle valves toward their closed positions.

The throttleinterconnection mechanism of Figs. 49 operates as follows:

Main throttle valves 23 may be opened by manual control lever 27 to approximately the position shown in Fig. 5 without affecting auxiliary throttle valves 24. At'this I -point,inward lug 63 on loose lever 55, which is yieldingly connected to the main throttle shaft through tension spring 59 and disk lever 57, abuts portion 64 of loose lever 56. Thereafter, continued opening of the main throttle valves rotates lever 56 counterclockwise and, through link 69 and crank 70, opens auxiliary throttle valves 24. i

a The leverage is such that the auxiliary throttles are. fully opened during the latter part of opening movement 'of the main throttles.

However, at low temperatures, with choke valve 22 at least partially closed, eccentric stop device 41 will be in the position of Fig., l to prevent opening of the auxiliary throttle valves and counterclockwise movementof lever 56; At such time, tension. spring 59 may stretch, "as shown in Fig. 6, permitting continued opening movement of the main throttle valves independently of the locked auxiliary throttles. p r 7 As previously mentioned, ,as the choke valve 22 'ap- 4 1 Each pair of fuel chambers 75 and 77 and 76 and 78 is connected by across portion 91 and 92 within which are a pair of main metering orifice elements 93 and 94, each connected to a main fuel passage 95 or 96 discharging through the usual venturi tube constructions into one of the mixture conduits. Forward, main fuel passages 95 are provided with idling systems including restriction tubes 97 and passages 98 communicating withthe usual idle ports 99 adjacent and posterior to the edges of main 7 throttle valves 23 when closed. The rear, auxiliary, mix-.

ture conduits are not provided withidling systems, in the form shown, although these maybe provided and may be interconnected with main passages 96 or may be chamber por-j supplied independently thereof from fuel tion-92.

Forward metering orifice elements 93 are controlled 7 by metering pins 10$ which are actuated in accordance with manifold vacuum and throttle positions by means-of V a suction piston liil working in a cylinder. 102 connected to the main mixture conduits posterior to thethrottle valves therein by means of a suction passage 103.

V Piston stem 104 at the top'carries a cross bar 105 which mounts, at its extremities, the two main metering pins 100. A small crank 106 carried on a journalled counter-' shaft 107 above fuel bowl portion 91 has a finger 108 a which underlies cross bar 105 soas to move the meter-.

' ing pins upwardly when the main throttle valves are proaches its full open position during normal warming up of the engine, eccentric stop lever 41 is shifted away from its locking position by fastidle cam lug 48, permitting normal functioning of the auxiliary throttle valves. i Fig. 7 illustrates the normal, wide open positioning of.

both throttle valves to supply the maximum quantity of During the first part of the on disc arm 57. rotates lever 55 clockwise, and with it inward finger 63, .thus permitting spring 71 to close the Whenthe main throttle valves,

position of Fig. 5, the auxiliary throttle'valves will be substantially fully closed and thereafter, the main throttle valves may be closed the rest of theway without afiectand 77 V and 78 within which are floats 79 and 80, in pairs, connected by yokes 81 and 82 to bifurcated'meml bers 83 and 84, pivotally supported by pins 85 and 86' i mounted,.respectively, in the central, forward and rear- 7 portions of .the carburetor bowl structure.

cated elementsengage and actuate needle valves 87 and 38 which control the admission of fuelthrough inlet 89 and passages 90 to the respective float bowls for maintaining fuel at a substantiallyconstant level therein.

The 'bifuropened. Countershaft 107 is connected to the mainthrottle valves by means of an arm 109 and link 110 (Figs. 1 and 10) connected at its lower extremity to main throttle control lever 27. This form of manual and vacuum control of the metering pins is covered in Read Patent No. 2,208,702.

Also provided in the forward portion 91 of the fuel it bowl structure (Fig. l) is an accelerating pump including a piston 112 Working in a cylinder 113 and connected to the throttle valve by means of a stem 114, link 115,

and crank 116 rigid with the aforementioned countershaft V 107. Upon opening movement of the main throttle valves, fuel is discharged into themain mixture conduits 15 and 16 through pump outlet passages 117 pastfoutlet check 118 and through discharge jets 119. V 7

7 Variousfeatures of the invention, particularly, theserial control .of the main and auxiliary throttle valvesand the arrangement for locking the 'auxiliary throttle valves may be incorporated in other'carburetion systems,

irrespective'of whether the number of mixture conduits or whether the conduits are integrated into a single carburetor or are included in multiple carburetors.

The invention may be modified in this and other re}- spects as will occur to those skilled in the art and the exclusive use of all modifications as come Within the scope of the appended claims is contemplated.

We claim: r

1. In a multi-stage carburetion system, a plurality of induction conduits, a main throttle in one of said 'conduits and an auxiliary throttle in another of said conduits,

a thermostatic stop device for restricting opening of said;

auxiliary throttle at low temperatures, and a lost motion,

resilient connection between said throttles comprising first and second arms movable, respectively, with said.

main and auxiliary throttles, first and second levers pivotally mounted with respect to said main throttle, a lost motion connection between said levers, a resilient connection between said first lever and the arm movable with said main throttle, and ,a rigid connection between said second lever and the arm movable with said auxil: 1

iary throttle.

2. A carburetion system as described in: claim 1 in.

which said main throttle is mounted on a pivoting shaft,

said first arm being rigidly mounted on said shaft and said first and ,second levers being rotatably .mounted about said shaft.

3. In a multi-stage carburetion system for an internal combustion engine, a main and .an auxiliary induction conduit, main and auxiliary throttles, respectively, in said conduits, a choke valve in said main conduit, 2. connection between said throttles for causing serial opening thereof, first and second arms rotatable, respectively, with said main and auxiliary throttles, a fast idle cam pivotally mounted adjacent said first arm and engageable thereby to adjust the'idling speed of the associated engine, a connection between said choke valve and cam, a stop device pivotally mounted adjacent said second arm and normally biased to a position to interfere with rotation of said sen ond arm and opening of said auxiliary throttle, and an operative connection between said cam and said stop device for shifting the latter from said position upon opening of said choke valve.

4. A carburetion system as described in claim 3 in which said conduits are located closely side by side and said fast idle cam and stop device are concentrically pivoted.

5. In a multi-stage, multi oarrel carburetor, a plurality of induction conduits arranged side by side as a unit, a main and an auxiliary throttle valve mounted each it one of said conduits and on parallel shafts, a thermostatic choke valve mounted in the air inlet portion of one of said conduits, an operative connection on one side of said carburetor unit between said choke valve and said auxiliary throttle valve for limiting opening of the lattez when said choke valve is closed, a manual control for said main throttle valve, and a resilient, operative connection between said throttles on the opposite side of said carburetor unit for causing serial opening thereof, said resilient connection comprising first and second arms movable, respectively, with said main and auxiliary throttle valves, first and second levers pivotally mounted about said main throttle shaft, a lostmotion connection between said levers for transmitting rotation from one to the other, a spring connecting a first one of said levers and said first arm movable with said main throttle, and a link connecting said second lever and said second arm movable with said auxiliary throttle valve.

6. In a multi-barrel, multi-stage carburetor unit for an internal combustion engine, a main and a secondary ire duction conduit, main and secondary throttles, respectively, in said conduits on parallel shafts, a choke valve in said main conduit, an operative connection between said choke valve and said secondary throttle comprising an arm rotatable with said secondary throttle, a stir? lever pivotally mounted adjacent said arm and normally biased to a position to interfere with rotation of said arm and consequent opening of said secondary throttle, and linkage connecting said choke and said stop lever for shifting said lever away from said normal position there of, upon opening of said choke valve, and a resilient operative connection between said throttle valves opposite said first-mentioned operative connection comprising first and second arms movable, respectively, with said main and secondary throttles, first and second levers pivoted about said main throttle shaft, a lost-motion connection between said levers for transmitting rotary motion therebetween, a spring connecting said first lever and said first arm movable with said main throttle, and a link connecting said second lever and said second arm movable with said secondary throttle.

7. In a multi-stage carburetor system, a plurality of induction conduits, a main throttle in one of said conduits, an auxiliary throttle in another of said conduits, a thermostatic stop device for restricting opening of said auxiliary throttle at low temperatures, and a lost motion resilient connection between said throttles comprising first and second arms movable, respectively, with said main and auxiliary throttles, first and second levers pivotally mounted with respect to said main throttle, a lost motion connection between said levers and between said levers and said first arm, a resilient connection between said first lever and the arm movable with said main throttle, and a rigid connection between said second lever and the arm movable with said auxiliary throttle.

8. In a multi-stage carburetor system for an internal combustion engine, main and auxiliary induction conduits, main and auxiliary throttles, respectively, in said conduits, a yielding connection between said throttles for causing serial opening thereof, an arm rotatable with said auxiliary throttle, a stop lever pivotally mounted adjacent said arm and normally biased to a position to interfere with rotation of said arm and opening of said auxiliary throttle, means for retaining said stop lever in locked position, said means being variable in its resistance to unlocking movement in accordance with the force exerted by said yielding connection, means responsive to air flow in said main conduit for overcoming the resistance of said retaining means, and temperature responsive means opposing the action of said means responsive to air flow, whereby said stop lever is released automatically when the primary throttle is open and the engine reaches normal operating temperatures.

9. In a multistage carburetion system for an internal combustion engine, a main and an auxiliary induction conduit, main and auxiliary throttles, respectively, in said conduits, a choke valve in said main conduit, a manual control for said main throttle, means to open said auxiliary throttle to increase the capacity of the system, first and second arms rotatable, respectively, with said main and auxiliary throttles, a fast idle cam pivotally mounted adjacent said first arm and engageable thereby to adjust the idling speed of the associated engine, a connection between said choke valve and cam, a stop device pivotally mounted adjacent said second arm and normally biased to a position to interfere with rotation of said second arm and opening of said auxiliary throttle, and an operative connection between said cam and said stop device for shifting the latter from said position upon opening of said choke valve.

References Cited in the file of this patent UNITED STATES PATENTS 2,193,533 Kishline et al. Mar. 12, 1940 2,328,763 Winkler Sept. 7, 1943 2,640,472 Bicknell June 2, 1953 

